Pipe railing is an extremely popular product. It is used on public as well as private projects throughout the United States. Places such as water treatment plants, computer platforms, loading docks, sidewalks, bicycle paths, amusement areas, shopping centers, hospitals and grandstands employ pipe railing for various purposes.
Prior art pipe railings exist but they all have serious deficiencies. The installation of the prior art railings usually poses serious problems which create unnecessary expense for the consumer. In addition, certain existing connectors suffer from inadequate strength and poor fitting of parts. These and other problems motivated the research which eventually led to the present invention.
Essentially, there are two very popular designs for post and rail connectors presently in existence. The first design employs a sleeve coupling which is, in essence, a short length of pipe having an outer diameter just slightly less than the inner diameter of the pipe rail. One half of this sleeve coupling is then inserted into a horizontal pipe section of a post assembly and welded to the inner surface of this horizontal pipe section. The remaining half of the sleeve protrudes from the horizontal pipe section of the post assembly. The pipe rail is then slipped over this protruding section of the sleeve and fastened thereto by either epoxy or screws.
This particular connector is common throughout the industry and is advantageous because it allows the pipe railing to be shipped in a knock-down configuration. However, this approach requires that there be a difference in diameter between the sleeve and the inner surface of the pipe rail so that the sleeve may be slipped over the pipe rail. This produces a loose fit between the pipe rail and connector which makes the connector act in a manner similar to a universal joint during installation This makes alignment and installation very difficult and time consuming especially when longer lengths of pipe rail are employed. Even short lengths of pipe cause significant alignment problems. These problems result in a high cost of erection and a finished product of dubious quality.
A second design for post and rail connectors involves the use of a stainless steel sheet metal connector having enough flexibility to yield to the inner diameter of the pipe rail. This type of connector eliminates the problem of having a loose fit between the pipe rail and the connector. On the other hand, this connector suffers from other significant disadvantages For instance, the short length and inherent flexibility of the stainless steel connectors cause a significant reduction in strength at the connection. Also, alignment is still a problem because the shortness of the protrusion into the pipe rail still allows the connection to function in a manner similar to a universal joint. Finally, the fabrication of this stainless steel connector requires a significant amount of machine operations to facilitate the connection.
A third design is the subject of a co-pending U.S. application Ser. No. 943,706, now U.S. Pat. No. 4,714,369, to the same inventor. The present invention is an improvement on the invention of the co-pending application.